BSD 4_1_snap development

[unix-history] / sys / h / vmparam.h

/*	vmparam.h	4.10	81/04/24	*/

/*
 * Machine dependent constants
 */
#define	NPTEPG		(NBPG/(sizeof (struct pte)))
					/* number of ptes per page */
#define	USRSTACK	(0x80000000-UPAGES*NBPG)
					/* Start of user stack */
#define	P1TOP		0x200000	/* boundary between P0 and P1 regions */

/*
 * Virtual memory related constants
 */
#define	SLOP	32
#define	MAXTSIZ		(6*2048-SLOP)		/* max text size (clicks) */
#define	MAXDSIZ		(12*1024-32-SLOP)	/* max data size (clicks) */
#define	MAXSSIZ		(12*1024-32-SLOP)	/* max stack size (clicks) */

/*
 * Sizes of the system and user portions of the system page table.
 */
/* SYSPTSIZE IS SILLY; IT SHOULD BE COMPUTED AT BOOT TIME */
#define	SYSPTSIZE	(12*NPTEPG)
#define	USRPTSIZE 	(8*NPTEPG)

/*
 * The size of the clock loop.
 */
#define	LOOPPAGES	(maxfree - firstfree)

/*
 * The time for a process to be blocked before being very swappable.
 * This is a number of seconds which the system takes as being a non-trivial
 * amount of real time.  You probably shouldn't change this;
 * it is used in subtle ways (fractions and multiples of it are, that is, like
 * half of a ``long time'', almost a long time, etc.)
 * It is related to human patience and other factors which don't really
 * change over time.
 */
#define	MAXSLP 		20

/*
 * A swapped in process is given a small amount of core without being bothered
 * by the page replacement algorithm.  Basically this says that if you are
 * swapped in you deserve some resources.  We protect the last SAFERSS
 * pages against paging and will just swap you out rather than paging you.
 * Note that each process has at least UPAGES+CLSIZE pages which are not
 * paged anyways (this is currently 8+2=10 pages or 5k bytes), so this
 * number just means a swapped in process is given around 25k bytes.
 * Just for fun: current memory prices are 4600$ a megabyte on VAX (4/22/81),
 * so we loan each swapped in process memory worth 100$, or just admit
 * that we don't consider it worthwhile and swap it out to disk which costs
 * $30/mb or about $0.75.
 */
#define	SAFERSS		32		/* nominal ``small'' resident set size
					   protected against replacement */

/*
 * DISKRPM is used to estimate the number of paging i/o operations
 * which one can expect from a single disk controller.
 */
#define	DISKRPM		60

/*
 * Klustering constants.  Klustering is the gathering
 * of pages together for pagein/pageout, while clustering
 * is the treatment of hardware page size as though it were
 * larger than it really is.
 *
 * KLMAX gives maximum cluster size in CLSIZE page (cluster-page)
 * units.  Note that KLMAX*CLSIZE must be <= DMMIN in dmap.h.
 */

#define	KLMAX	(32/CLSIZE)
#define	KLSEQL	(16/CLSIZE)		/* in klust if vadvise(VA_SEQL) */
#define	KLIN	(8/CLSIZE)		/* default data/stack in klust */
#define	KLTXT	(4/CLSIZE)		/* default text in klust */
#define	KLOUT	(32/CLSIZE)

/*
 * KLSDIST is the advance or retard of the fifo reclaim for sequential
 * processes data space.
 */
#define	KLSDIST	3		/* klusters advance/retard for seq. fifo */

#ifdef KERNEL
int	klseql;
int	klsdist;
int	klin;
int	kltxt;
int	klout;
#endif